NP++ has two available keyboard shortcuts for: Fold all (Alt + 0), Unfold all (Alt + Shift + 0).
But it’s waste of keyboard and memory to remember those two for one type of action.
New would be like: “Toggle Fold All”. When you press it once, it will do opposite as it is in file (will fold everything in fresh opened document), when pressed again, will unfold everything back.
Similar thing we have for comments. To toggle (Ctrl + Q).
Nontheless, I have tried to bind both actions to one keyboard button. Didn’t work. Which leads me towards:

Second feature would be handy, if NP++ will be able to show warning to user, for conflict situation about assigning same keyboard bind to two or more actions. Like above.
For example, when you install some plugin, but it will have binded already some shortcut by default. Which may be same as in your personal keybind somewhere for other action.
Now, you have to going through all keybinds in Shortcut mapper manually. Moreover, this plugin, won’t help you anything in this situation - NppMenuSearch.
Because it can’t even find my keybind for duplicate for example: Ctrl + D. I have tried to search in it, without spaces, first letter capital, no capitals…
Please realize, that we don’t know which shortcut is in conflict, so we have to search for keybind, not for action (shortcut) !
So plugin is bad. Which leads me to:

Third feature proposal is about making default NP++'s feature instead of plugin, which is not working as expected: NppMenuSearch.
It’s good idea and very useful (other notepads have it too in default) to have it, but correcly.
I’m talking about unable to get into place of searched thing. Unability to open that window where found item is located + highlight it of course.
Example: I search for keyboard shortcut “Fold all”. It finds it ok, but when I press Enter to get me to that place, nothing will happen.
So I guess, as a plugin, it has no access to everything in NP++. But when this feature would be inside of NP++ as default, it would opens for user that Shortcut mapper window, WITH highlighted row for my “Fold all” shortcut.

it will be as as it is now - NP++ will do it one of those actions if i tried alt+0 or alt+shift+0. point is, the first press, make whole document on same level. if you dont like, second press will make it as you need. got me ?
one of both actions will work. and it will make whole document consistent. all folded or unfolded.